From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751693Ab2LSWNz (ORCPT ); Wed, 19 Dec 2012 17:13:55 -0500 Received: from mail.savoirfairelinux.com ([209.172.62.77]:36290 "EHLO mail.savoirfairelinux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750796Ab2LSWNt (ORCPT ); Wed, 19 Dec 2012 17:13:49 -0500 Date: Wed, 19 Dec 2012 17:13:47 -0500 (EST) From: Vivien Didelot To: Grant Likely Cc: linux-kernel@vger.kernel.org, Jerome Oufella , Linus Walleij Message-ID: <1032450702.626703.1355955227194.JavaMail.root@mail.savoirfairelinux.com> In-Reply-To: <20121219171600.7B0EF3E0C5A@localhost> Subject: Re: [PATCH v2] gpio: add TS-5500 DIO blocks support MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [208.88.110.46] X-Mailer: Zimbra 7.1.4_GA_2555 (ZimbraWebClient - FF3.0 (Linux)/7.1.4_GA_2555) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Grant, > Please take a look at either send me a follow-on patch to convert it > to use gpio-generic, or tell my why gpio-generic isn't appropriate here. The gpio-generic driver is not appropriate here because Technologic Systems x86-based platforms do not use a typical GPIO implementation. To name a few specificities: - The GPIOs are available through ioport and not iomem - There are input-only/output-only/input-output lines on the same block - The number of GPIOs differs between blocks (currently 11, 13 and 14 pins) - A single bit in a control register drives the direction of 4 input/output lines, while the register's other bits have different functions. IMHO these considerations justify a specific GPIO driver to support these Technologic Systems pin blocks. Regards, Vivien